Application of Combined Cuttings Gas/Oil Analysis, Rapid XRF and High Resolution Photography to Evaluation of Unconventional Reservoirs

Hall, Don L.; Sterner, Mike

Exploration and exploitation of increasingly complex reservoirs, along with technical challenges associated with optimizing horizontal wells into tight or unconventional pay sections benefit from integrated rock-fluid data. Herein we describe one such methodology applicable to unpreserved cuttings from entire boreholes. The rock is photographed under visible and UV light, crushed and analyzed for included hydrocarbon and non-hydrocarbon volatile species via direct quadrupole mass spectrometry, and finally analyzed via XRF for its elemental composition. A key aspect of the procedure is that all analyses are conducted on the same small sample with automated instrumentation, and resulting data can be interrogated simultaneously using a special viewer. Thus, interrelationships among rock type, fluid type and rock chemistry are preserved. The approach provides insights into the controls on hydrocarbon, reservoir and pay distribution, and can be used an additional tool for well placement. Examples from three unconventional reservoirs will be used to illustrate the broad variety of questions that can be addressed with this approach. These include: 1) Present and past petroleum distribution, 2) Petroleum source, maturity and chemistry, 3) Rock and cement type and distribution, 4) Chemical stratigraphy for correlation and retrospective borehole trajectory verification, 5) Mineralogical trends necessary for log calculations, 6) Depositional environments, 7) Source rock potential and 8) Rock properties relevant to completion.

AAPG Search and Discovery Article #90163©2013AAPG 2013 Annual Convention and Exhibition, Pittsburgh, Pennsylvania, May 19-22, 2013